This invention is generally concerned with printing apparatus for marking letters and more particularly with flat bed printing apparatus for marking letters including envelopes, stuffed envelopes, irregularly-shaped letters and letter mail, including self-mailers and stepped mail.
A significant proportion of the approximately one-half billion irregularly-shaped letters, flats, parcels, and other irregularly-shaped mailpieces, such as stepped letter mail, hotel keys, bagged film and the like, which are annually received by the U.S. Postal Service for processing, must be manually processed due to the lack of automated equipment. In the case of stepped, and other irregularly-shaped letter mail, automatic separation equipment is available for separating such mail from the main stream of incoming mailpieces, but there has been a long felt need for reliable machinery for handling other processing tasks. In particular, manual processing is heavily relied upon for performing such functions as cancelling the postage of stepped and other irregularly-shaped letter mail, and marking the same with appropriate destination bar codes for subsequent sorting. Moreover, the marking function implemented in the course of processing irregularly-shaped letter mail ranks amongst the highest of the labor intensive activities engaged in by Postal Services on a worldwide basis.
Of course, large private mailers of stepped and other irregularly-shaped letters are similarly burdened with labor intensive processing activities, including applying addresses, postage indicia and bar codes to such letters for delivery to the Postal Service.
For marking letters, such as envelopes, stuffed envelopes, irregularly-shaped letters and letter mail including self-mailers and stepped mail, mailing machines have been provided with postage printing apparatus which includes indicia marking structure and platen structure including a platen having an elastomeric member mounted thereon. To accommodate marking letters of varying thicknesses fed to the platen structure, the platen is lowered to receive a given letter on the elastomeric member, and then raised towards the indicia marking structure for marking the letter. In this connection, reference is made to U.S. patent application Ser. No. 135,186 for a Platen Module For A Modular Mailing Machine, filed Dec. 18, 1987 by Jovito N. Abellana et al and assigned to the assignee of the present invention, the subject matter of which is incorporated in this application by reference.
Moreover, thermal transfer printing apparatus of the type which includes a thermal printhead and thermal ink transfer ribbon, has been provided with a flexible roller for applying backing pressure to a letter fed between the ribbon and roller as the thermal printhead heats and applies pressure to the ribbon for transferring ink from the ribbon to the letter for marking the same. In this connection, reference is made to U.S. patent application Ser. No. 138,427 for Apparatus For Processing Irregularly-Shaped Letters In A Thermal Printer, filed Dec. 28, 1987 by Patrick Murphy et al and assigned to the assignee of the present invention, now Pat. No. 4,857,942 issued Aug. 15, 1989, and the references cited therein.
The flexible roller embodiments shown in the aforesaid Murphy et al Application include those having a cylindrically-shaped body portion provided with one or more channels extending thereinto from the outer surface of the body portion, as a result of which a plurality of spaced apart portions of the roller body portion contact a given letter fed to the thermal printer along a line extending transverse to the path of travel of both the thermal ink transfer ribbon and the given letter. And, one of the roller embodiments shown in the Murphy et al Application has a cylindrically-shaped roller body portion including one or more apertures formed therein and extending longitudinally of the length of the roller body portion.
It has been found that the printing quality of printing on letters, including envelopes, stuffed envelopes, irregularly-shaped letters and letter mail, including self-mailers and stepped mail, in a flat bed printer, is enhanced by providing an improvement in the platen member mounted on the platen of the platen module disclosed in the aforesaid Abellana et al Application. The improved platen member is preferably a resilient member, made of an elastic material, and includes a plurality of intersecting channels which extend upwardly from the inner surface of the member, rather than downwardly from the outer surface of the member, whereby the member does not include the spaced-apart letter contacting portions, or the apertures, shown in the Murphy et al Application. Moreover, it has been found that since the flexibility of the improved member in a flat bed printer affords the application of varying back pressure, against the printing die of the postage metering module, the grey scale level of the print on letters is substantially completely uniform. Accordingly:
An object of the invention is to provide apparatus for enhancing the printing quality provided by flat bed printing apparatus;
Another object is to provide improved apparatus for marking letters;
Another object to provide apparatus including improved means for resiliently urging a letter into engagement with a printing die;
Another object is to provide means for variably, resiliently supporting letters against the force exerted thereon by a printing die;
Another object is to provide a reciprocable platen, having a resilient, channeled, member mounted thereon, for use in flat bed printing apparatus;
Yet another object is to provide a platen assembly which includes a pair of rack gears, a platen integrally connected to the upper ends of the rack gear and supporting structure extending between the rack gears, which are manufactured as a single piece part, in combination with a resilient platen member according to the invention; and
Another object is to provide flat bed printing apparatus which includes a flexible member, having a plurality of intersecting channels formed therein, mounted on platen which is reciprocable for movement of the member toward and away from a printing die.